Numerous studies have been directed towards the effect of fatty acids on blood clotting with the lack of mechanistic evaluation and systematic approaches. Although attempts have been made to define the role of fatty acids in platelet aggregation and hyper-coaguability, little work has been done in the area of thrombogenicity relating to artificial and natural blood vessel surfaces. In this application, we propose to: 1. Investigate whether initial thrombus formation at polymer or natural blood vessel interface is induced and/or accelerated by adsorbed fatty acids. 2. Study the subsequent release of adsorbed fatty acids, which results in a high concentration of the fatty acids at the interface and can induce platelet aggregation. 3. Determine possible endothelial cell damage caused by adsorbed fatty acids via in vitro and in vivo animal experiments. 4. Characterize binding constants of fatty acids to plasma albumin. 5. Correlate physiochemical properties of fatty acid suspensions with platelet aggregation. It is expected that the results obtained will be valuable in understanding the phenomenon of blood vessel damage, occlusive vascular disease, atherosclerosis, and will aid in the design of hemocompatible materials.